GB/T 4324.26-1984 Chemical analysis of tungsten - Photometric determination of nitrogen with Nessler reagent GB/T4324.26-1984 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Methods for chemical analysis of tungsten
Nessler reagent photometric method for thedetermination of nilrogen content
Methods for chemical analysis of tungstenThe Nessler reagent photometric method for thedetermination of nilrogen contentThis standard is applicable to the determination of nitrogen in pigeon powder and pigeon strips. Determination range: 0.0010～0.0050%. This standard complies with GB1467-78 "General Principles and General Provisions of Chemical Analysis Methods for Metallurgical Products", 1 Method Summary
UDC669.271548
.42:546.17
GB 4324.26-84
The sample is heated and decomposed with potassium sulfate and sulfuric acid in a grinding sample bottle with a gas condensing device, and then transferred to a distiller made by Kjeldahl principle, distilled with sodium hydroxide, absorbed with dilute sulfuric acid, and determined by Nessler reagent colorimetrically. 12 Reagents
2.1 Potassium sulfate.
2.2 Sulfuric acid (specific gravity 1.84), high purity. 2.3 Sulfuric acid (1 + 1)
2.↓ Sulfuric acid absorption solution: add 1 ml of sulfuric acid (2.2) to 1000 ml of ammonia-free distilled water. 2. Sodium hydroxide solution (50%), add 800 ml of water and 400 ml of sodium hydroxide to a 1000 ml conical flask, mix after dissolving, boil, and concentrate the solution to 800 ml.
2.6 Nessler's reagent
2.6,1 Weigh 100 g of mercuric iodide and 70 g of potassium carbide, dissolve in 100 ml of water. 1.2. Pipette 160 g of sodium hydroxide in 700 ml of water and cool to room temperature. 2..3 Pour solution (2.6.1) slowly into solution (2.6.2) under constant stirring, dilute with water to 1000ml, store in brown medium, and place! Zhoudian takes clean water and uses
2.7 Nitrogen standard solubility
2.7.1 Weigh 4.7190g of dead water ammonium sulfate (superior grade) or 3.8190g of anhydrous ammonium chloride (superior grade), place in a beaker, dissolve with water, transfer to a 10ml volumetric bottle, dilute to the mark with water, and mix. This solution contains 1.0m nitrogen per ml. 2.7.2 Transfer 10.00ml of nitrogen standard solution (2.7.1), place in a 1000ml volumetric flask, dilute to the mark with water, and mix. 1 ml of this dense liquid contains 2.8 mg nitrogen
2.8 mg hydrogen distilled water: add 15 ml sulfuric acid (2.2) and 20 ml potassium permanganate solution (4%) to 10000 ml distilled water, mix, and steam (this method uses this water). 2.8 zinc particles.
3. Sample dissolving bottle, see Figure 1.
3.2 Distillation device, see Figure 2.
Standards Bureau of China 1384-04-1 2 Issued 0
1985-03-01 Implementation
Tungsten bars should be crushed and passed through a 120-month sieve.
5 Analysis steps
5.1 Determination quantitybzxZ.net
GB 4324.2684
Sample bottle
Figure 2 Distillation apparatus
During analysis, three samples should be weighed for determination. The measured values ​​should be within the allowable indoor difference and the average value should be taken. 5.2 Sample quantity
Weigh 1.000g sample.
5.3 Blank test
Carry out a blank test along with the sample.
5. 4 Determination
GB 4324.26—84
5.4.1 Place the sample (5.2) in a 250ml sample bottle, add 6g potassium sulfate (2.1) and 10ml sulfuric acid (2.2), heat until the sample is dissolved, cool, and rinse the bottle stopper and bottle wall with water. 5.4.2 Transfer the solution to a distillation bottle, add 50ml sodium hydroxide solution (2.5), and dilute with water to 200ml. Connect the distillation device.
5.4.3 Send steam for distillation, collect the distillate in a 50ml colorimetric tube pre-filled with 10ml sulfuric acid absorption solution (2.4), and distill until the volume of the absorption solution is about 45ml.
5.4.4 Remove the colorimetric tube, add 1ml Nessler's reagent (2.6.3) and dilute with water to the scale. Mix well and let stand for 10 minutes. 5.4.5 Transfer part of the solution to a 3 cm colorimetric dish and measure its photometry at a wavelength of 420 nm using water as a reference on a spectrophotometer. 5.4.6 Subtract the absorbance of the sample. Find the corresponding nitrogen content from the working curve. 5.5 Drawing of the working curve
Add 10 ml of sulfuric acid absorption solution (2.4) to a set of 50 ml colorimetric tubes, then add 0.00, 0.50, 1.00, 2.00, $.00, 4.00, 5.00 ml of nitrogen standard solution (2.7.2) respectively, dilute to 45 ml with water, add 1 ml of Nessler reagent (2.6.3), dilute to the scale with water, mix well, and let stand for 10 minutes. The following is carried out according to 5.4.5, measure its absorbance, and subtract the absorbance of the reagent. Draw the working curve with nitrogen content as the horizontal axis and absorbance as the vertical axis. 6 Calculation of analysis results
Calculate the percentage of nitrogen according to the following formula:
N(%)=
Where: m——Nitrogen content found from the digraph, g, a-Sample volume, g:
7 Permissible difference
The difference in analysis results between laboratories should not be greater than the permissible difference listed in the following table.
0.0010-0.0020
>0.0020-0.0050
Additional remarks:
This standard is proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard is drafted by Zhuzhou Cemented Carbide Factory. The main drafters of this standard are Chen Guohua and Chen Fuhao.
From the date of implementation of this standard, the former Ministry of Metallurgical Industry Standard YB895-77 "Chemical Analysis Method" shall be invalid. 92
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